The invention relates generally to welding-type systems, and more particularly to methods and apparatus for detecting leakage current.
Welding, plasma cutting, and induction heating power supplies are well known. Typically, such power supplies do not have a ground fault interrupt circuit, but rather include reduced open circuit output voltages, low current, high frequency starting circuits, and cautionary labels. However, it is difficult to provide a reduced output voltage for induction heating. Ground fault interrupting circuits are known outside the welding, plasma cutting, and induction heating industry, but using known ground fault interrupting circuits in the welding, plasma cutting, and induction heating industry is difficult because of the nature of the power supplies and the environments in which they are used.
It is desirable to have a welding, plasma cutting, and/or induction heating power supply with a low voltage ground fault protection circuit that has a low current threshold but is not adversely susceptible to the high frequency noise typically generated by welding, plasma cutting, and induction heating power supplies.